Biologically important molecules (except protein)

What is organic chemistry?

The study of compounds that contain carbon.

What are organic compounds?

Compounds that contain carbon and hydrogen.

What is the importance of carbon in living things?

Carbon forms four bonds, allowing it to create a huge variety of organic molecules.

What is the difference between organic and inorganic compounds?

Organic compounds contain carbon and hydrogen; inorganic compounds generally do not contain both.

Is glucose (C6H12O6) organic or inorganic?

Organic.

Is methane (CH4) organic or inorganic?

Organic.

Is water (H2O) organic or inorganic?

Inorganic.

Is carbon dioxide (CO2) organic or inorganic?

Inorganic.

Is sodium chloride (NaCl) organic or inorganic?

Inorganic.

Is hydrochloric acid (HCl) organic or inorganic?

Inorganic.

What is abiotic synthesis?

The formation of compounds through nonliving chemical processes.

What is a decomposition reaction?

A chemical reaction that breaks a larger molecule into smaller molecules.

What is the general chemical notation for decomposition?

AB → A + B.

What happens to covalent bond energy during decomposition, according to the slides?

Covalent bond energy is released.

What is a synthesis reaction?

A chemical reaction in which smaller molecules combine to form a larger molecule.

What is the general chemical notation for synthesis?

A + B → AB.

What happens to energy during synthesis, according to the slides?

Energy is absorbed.

What is hydrolysis?

A decomposition reaction that uses water to break bonds.

What does hydrolysis mean literally?

Breaking apart using water.

What is an example of hydrolysis in living organisms?

Food digestion.

What is dehydration synthesis?

A reaction that joins molecules by removing water and forming a new bond.

What is removed during dehydration synthesis?

A water molecule (H2O).

How do hydrolysis and dehydration synthesis differ?

Hydrolysis adds water to break bonds; dehydration synthesis removes water to form bonds.

What is a polymer?

A long molecule consisting of many similar building blocks.

What is a monomer?

A small repeating unit that serves as a building block for polymers.

What is the relationship between monomers and polymers?

Many monomers can join together to form a polymer.

What are carbohydrates?

Biological molecules that include sugars and polymers of sugars.

What is a monosaccharide?

A simple sugar and the simplest type of carbohydrate.

What does the prefix mono- mean?

One.

What is a polysaccharide?

A polymer composed of many sugar building blocks.

What does the prefix poly- mean?

Many.

What are two functions of monosaccharides?

They provide major fuel for cells and serve as raw materials for building other molecules.

What shape do monosaccharides usually form in aqueous solutions?

Rings.

How are disaccharides formed?

Two monosaccharides join through dehydration synthesis.

What does the prefix di- mean?

Two.

What is the usual general formula pattern for monosaccharides?

A molecular formula that is usually a multiple of CH2O.

What is starch?

A storage polysaccharide in plants made of glucose monomers.

Where is surplus starch stored in plants?

In granules within chloroplasts and other plastids.

What is glycogen?

A storage polysaccharide in animals.

Where is glycogen stored?

In liver and muscle cells.

What is cellulose?

A glucose polymer that is a major component of the tough walls of plant cells.

What is chitin?

A structural polysaccharide found in arthropod exoskeletons and the cell walls of many fungi.

What is the difference between starch and glycogen?

Starch stores carbohydrates in plants, while glycogen stores carbohydrates in animals.

What is the difference between starch and cellulose?

Starch is used for energy storage in plants; cellulose provides structural support in plant cell walls.

What is the difference between a storage polysaccharide and a structural polysaccharide?

Storage polysaccharides store energy; structural polysaccharides provide support and strength.

Do lipids form polymers?

No. Lipids do not form polymers.

What does hydrophobic mean?

Repelled by water or having little or no affinity for water.

Why are lipids hydrophobic?

They consist mostly of hydrocarbons with nonpolar covalent bonds.

What are three major types of lipids?

Fats, phospholipids, and steroids.

What are fats made of?

Glycerol and fatty acids.

What is glycerol?

A three-carbon alcohol with a hydroxyl group attached to each carbon.

What is a fatty acid?

A molecule with a carboxyl group attached to a long carbon skeleton.

What is an ester linkage?

The bond that joins fatty acids to glycerol in a triglyceride.

What is a triglyceride?

A molecule formed when three fatty acids join to one glycerol molecule through ester linkages.

What are two ways fatty acids can differ?

They can differ in length and in the number and locations of double bonds.

What is a saturated fatty acid?

A fatty acid with no double bonds and the maximum number of hydrogen atoms possible.

What types of fats commonly contain saturated fatty acids?

Animal fats.

What is a typical property of saturated fats at room temperature?

They are usually solid.

What health concern is associated with saturated fats in the slides?

They can contribute to cardiovascular disease through plaque deposits.

What is an unsaturated fatty acid?

A fatty acid with one or more double bonds.

What types of fats commonly contain unsaturated fatty acids?

Plant and fish fats.

What is a typical property of unsaturated fats at room temperature?

They are usually liquid and are called oils.

What is the main function of fats in the slides?

Energy storage.

What is a phospholipid made of?

Glycerol, two fatty acids, and a phosphate group.

Which part of a phospholipid is hydrophobic?

The fatty acid tails.

Which part of a phospholipid is hydrophilic?

The phosphate-containing head.

What does hydrophilic mean?

Attracted to water or able to interact with water.

What happens when phospholipids are added to water?

They self-assemble into a bilayer, with their hydrophobic tails pointing toward the interior.

What is the main function of phospholipids?

They form the bilayer of cell membranes.

Why do phospholipids form a bilayer in water?

The hydrophilic heads interact with water while the hydrophobic tails turn inward, away from water.

What is a steroid?

A lipid with a carbon skeleton consisting of four fused rings.

What is an example of a steroid?

Cholesterol.

What is one function of cholesterol?

It is a component of animal cell membranes.

What health concern is associated with high cholesterol levels in the blood?

They may contribute to cardiovascular disease.

What are nucleic acids?

Molecules that store or help use genetic information.

What are the two types of nucleic acids?

DNA and RNA.

What does DNA stand for?

Deoxyribonucleic acid.

What does RNA stand for?

Ribonucleic acid.

What are the monomers of nucleic acids?

Nucleotides.

What are polymers of nucleotides called?

Polynucleotides.

What are the three parts of a nucleotide?

A nitrogenous base, a pentose sugar, and a phosphate group.

What is a pentose sugar?

A sugar containing five carbon atoms.

Which sugars can occur in nucleotides?

Ribose or deoxyribose.

What is the main function of DNA?

It stores genetic information and provides directions for its own replication.

What does DNA direct the synthesis of?

Messenger RNA (mRNA).

How does DNA control protein synthesis?

DNA directs the synthesis of mRNA, which helps control protein synthesis.

Where does protein synthesis occur?

In ribosomes.

What is a gene?

A unit of inheritance made of DNA that programs the amino acid sequence of a polypeptide.

What shape does DNA form?

A double helix made of two polynucleotide strands spiraling around an imaginary axis.

What does antiparallel mean in DNA?

The two strands run in opposite 5′ to 3′ directions.

Which nitrogenous bases pair in DNA?

Adenine pairs with thymine (A–T), and guanine pairs with cytosine (G–C).

What type of bonds connect complementary DNA bases?

Hydrogen bonds.

What is the main role of RNA?

It is important in protein synthesis.

What are the three types of RNA?

Ribosomal RNA (rRNA), messenger RNA (mRNA), and transfer RNA (tRNA).

What sugar does DNA contain?

Deoxyribose.

What sugar does RNA contain?

Ribose.

Which nitrogenous bases are found in DNA?

Adenine, thymine, cytosine, and guanine (A, T, C, G).

Which nitrogenous bases are found in RNA?

Adenine, uracil, cytosine, and guanine (A, U, C, G).

Which base occurs in RNA instead of thymine?

Uracil.

Is DNA usually single-stranded or double-stranded?

Double-stranded.